Using flameless atom-absorption spectroscopy, the mercury concentration in the urine and in the blood of 102 persons was determined in a double-blind experiment. The subjects were divided into four groups: persons with and without amalgam fillings as well as persons with and without occupational contact with mercury and amalgam. Mercury concentrations in the blood and the urine were the same in relation to the presence or absence of amalgam fillings. The individual values varied, depending on the nutrition, and did not correlate with the number of amalgam fillings present in the individual case. Persons with occupational contact with mercury and amalgam excreted slightly more mercury in the urine. Even these values however were far below the upper limits of the range of normalcy.

Dental Amalgam↗

PubMed1979

[Uses of the occlusal registration instrument (ORI)].

By means of the occlusal recording instrument (ORI), jaw models can be measured three-dimensionally and filed with respect to axes and skull. In clinical trials evaluated with the ORI, it was shown that the position of the maxilla in the skull can be transferred to the articulator with great accuracy. Suggestions are given for improvements to refine the method of measurement. If the third point of reference is also tattooed, the accuracy of the transference of the face-bow is considerably increased. Under these conditions the apparatus is suitable for checking the accuracy of the transference of the face-bow and for photographic documentation.

Dental Articulators↗

PubMedDate not supplied

Dentin bond strength and marginal adaptation: direct composite resins vs ceramic inlays.

The aim of this in vitro study was to compare the dentin bond strength and marginal adaptation of directly and indirectly inserted restorations. A conically modified push-out test was designed to consider polymerization shrinkage and facilitate inlay placement. A total of 260 cavities were prepared into disks of freshly extracted human third molars and filled with direct composite resins or with adhesively luted ceramic inlays. Dentin adhesives of the third--(with self-etching primer: ART Bond, Syntac Classic), fourth--(with total etching: Scotchbond Multi-Purpose Plus), and fifth-generation (one-bottle adhesives: Syntac Single Component, Prime & Bond 2.1) were used in combination with one hybrid composite (Tetric) or luting composite (Variolink Low). Control groups did not use an adhesive. Polymerization of the bonding agent was carried out prior to insertion of the filling/inlay or afterwards simultaneously with the composite/luting composite. The thickness of the adhesive layer and luting composite was recorded, and after 7 days of storage and 24 hours of thermocycling (1150 cycles) replicas were made and extrusion testing performed. Fracture modes were determined and replicas were examined regarding marginal adaptation using SEM (X200 magnification). Precuring of the bonding resin increased dentin bond strength independent of the material combination or insertion mode (P < 0.05). In general, third- and fourth-generation dentin adhesives produced better results in bond strength and marginal adaptation than one-bottle systems (P < 0.05). In the third generation, ART Bond achieved significantly higher push-out values than Syntac (P < 0.05), but no better marginal adaptation. Cohesive fractures within the dentin were only observed in the inlay groups with precured resin. Precuring of the bonding resin is an important factor for both direct and indirect restorations. Nevertheless, precuring of the bonding resin prior to insertion of adhesive inlays cannot be recommended clinically, because the 120-micron luting spaces were too large. In simulated cavities, direct composite fillings with precuring achieved bond strengths similar to inlays without precuring. One-bottle adhesive systems performed poorly compared with multi-step adhesives of the third and fourth generation.

Analysis of Variance↗

PubMedDate not supplied

Long-term effect of dentin primers on enamel bond strength and marginal adaptation.

Contamination of etched enamel with dentin adhesive systems is unavoidable in clinical situations. The aim of this in vitro study was to evaluate the long-term effect of dentin adhesives and application technique on resin composite bond strength and marginal adaptation to enamel. Six hundred freshly extracted mandibular bovine incisors were used. Three hundred teeth were flat ground, and the enamel was etched for 30 seconds with 32% phosphoric acid. The etched surface was treated by different dentin adhesive systems with and without intensive rubbing by use of application brushes. As a control, only the enamel adhesive resin was applied and air thinned. Furthermore, contamination with saliva was performed after the etching process. Etched and silanated CEREC blocks were bonded onto the enamel specimens with different adhesive resins and stored for 1 and 365 days (37 degrees C, aqua dest). After storage, the specimens were thermocycled for 24 hours (1150 cycles between 5 degrees C and 55 degrees C), and subjected to shear bond testing. Three hundred box-shaped cavities were prepared on buccal surfaces of the incisors and filled with one resin composite using the same pretreatment modes as in the shear bond test groups. After 1 and 365 days of storage, a margin analysis was performed using a SEM (X200 magnification). Dentin adhesive systems did not show an adverse effect on long-term enamel bond strength and marginal adaptation. Rubbing application of the primers decreased the bond strength by values of approximately 20% after 24 hours and approximately 40% after 1 year of storage. Marginal adaptation showed 94-98% gap-free margins in the control and dentin adhesive system-only groups; however, after rubbing of primers, the proportion of gap-free margins decreased significantly to 85-88%. The lowest bond strength (8-10 MPa) and margin quality (49-69% gap-free margins) were recorded for the groups with saliva contamination.

Animals↗

PubMedDate not supplied

Dentin bond strength and marginal adaption after NaOCl pre-treatment.

The aim of this in vitro study was to compare the dentin bond strength and marginal adaptation of direct composite resins with and without additional NaOCl treatment after the etching process. A total of 150 cavities were prepared into disks of freshly extracted human third molars and filled with direct composite resins. Dentin adhesives of the fourth (with total etching: Scotchbond Multi-Purpose Plus, EBS, and Solid Bond), and fifth generation (one-bottle adhesives: Prime&Bond 2.1, Syntac Sprint) were used in combination with corresponding composite resin materials. Dentin disks without cavity preparation treatment served as controls. After 24 hours of storage and 24 hours of thermocycling (1150 cycles), replicas were made and push-out testing was performed. Replicas were examined regarding marginal adaptation using SEM (X200 magnification). In general, fourth-generation dentin adhesives produced better results in bond strength and marginal adaptation than fifth-generation one-bottle systems (P < 0.05). Within the fourth generation, Scotchbond Multi-Purpose Plus and EBS achieved significantly higher push-out values and percentages of gap-free margins than Solid Bond (P < 0.05). After hypochlorite treatment, dentin bond strength (-25%) and marginal adaptation (-30%) decreased significantly (P < 0.05) in all groups.

Acetone↗

PubMedDate not supplied

Technique sensitivity of dentin bonding: effect of application mistakes on bond strength and marginal adaptation.

This in vitro study evaluated dentin bond strength and marginal adaptation of direct resin composites according to the manufacturers' instructions and with simulated application errors. One hundred and forty cavities were prepared into disks of freshly extracted human third molars and filled with one resin composite. Dentin adhesives of the third (with self-etching primer: Syntac Classic), fourth (with total etching: Scotchbond Multi-Purpose Plus) and fifth generation (one-bottle adhesive: Prime&Bond 2.1) were used for bonding. Simulated application mistakes were as follows: 1) prolonged etching; 2) excessive drying after conditioning; 3) drying primers immediately after application and 4) drying primers excessively. After 21 days of storage and 24 hours thermocycling (1150 cycles), replicas were made and push-out testing was performed. Replicas were examined for marginal adaptation using SEM (X200 magnification). Compared with values of the control groups, application errors resulted in dramatically decreased bond strengths and reduced percentages of gap-free margins for all products tested (p < 0.05). Excessive drying after conditioning exhibited significantly less effect for the third generation adhesive than for products requiring total etching/wet bonding.

Acid Etching, Dental↗

PubMedDate not supplied

Leucite-reinforced glass ceramic inlays and onlays after six years: clinical behavior.

Ceramic inlays are an esthetic substitute for large amalgam and other metallic restorations. This controlled clinical study evaluated the performance of IPS Empress inlays and onlays with cuspal replacements and proximal margins below the cementoenamel junction over six years of clinical service. Six dentists placed 96 ceramic restorations in 34 patients. Luting was accomplished using the enamel-etch-technique, a dentin bonding system (Syntac Classic) and four different composite systems. The restorations were assessed by two calibrated investigators using modified USPHS criteria at baseline (96 restorations), one (96), two (95), four (89) and six years (67). Seven of the 96 restorations investigated had to be replaced (failure rate 7%; Kaplan-Meier): Five inlays suffered cohesive bulk fractures and two teeth required endodontic treatment. After six years of clinical service, significant deterioration (Friedman 2-way ANOVA; p < 0.05) was found for marginal adaptation of the remaining restorations. Ninety-four percent of the surviving restorations exhibited marginal deficiencies, independent of the luting composite. Neither the absence of enamel margins, nor cuspal replacement significantly affected the quality of the restorations.

Acid Etching, Dental↗